chore(deps): bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/publish.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-slim
     environment: release
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with: # Load existing tags to avoid duplicate tag error
           fetch-depth: 0
           fetch-tags: true

.github/workflows/rubocop-analysis.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1

.github/workflows/ruby.yml

@@ -19,7 +19,7 @@ jobs:
         ruby: [3.2, 3.3, 3.4]
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with: